An external fixation system comprising: first and second planar at least part-circular ring elements, the first ring element having a circumferential track extending along the part-circular circumference thereof; a plurality of struts each having a first and second end, the first end of each strut coupled to the first ring by a first connector and the second end of each strut coupled to a second ring by a second connector, the first connector including a spherical joint; the second connector non-rotatably coupled to the second ring, the strut second end being coupled to the second connector by a U-joint; shuttles mounted on the track of the first ring for movement there along with one shuttle coupled to each strut; and means for controlling the angular position of each strut second end and means for controlling the position of each shuttle along the circumferential track on the first ring.
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1. An external fixation system comprising:
first and second ring elements, the first ring including a gear track around a circumference thereof;
three shuttles mounted on the first ring element for controlled movement about a circumference of the first ring element each shuttle having a first connector including a joint having three degrees of freedom and the system having three second connectors fixed to the second ring, the three shuttles having a gear engaging the gear track on the first ring;
three kinematic chains each having first ends connected to a respective shuttle by the first connector and a second end connected to a respective second connector, the second connector non-rotatably mounted on the second ring, the second connector having a universal joint freely rotatable about a first axis parallel to the second ring element and rotatable in a controlled manner about a second axis perpendicular to the first axis; and
drive means for controlling the movement of each shuttle about the circumference of the first ring and for controlling the movement of the kinematic chain second end about the second axis of the second connector on the second ring.
4. An external fixation system comprising:
first and second planar at least part-circular ring elements, centers of the first and second ring elements spaced along an axis, the first ring element having a circumferential gear track extending along the part-circular circumference thereof;
three and only three struts each having a first and second end, the first end of each strut coupled to the first ring by a first connector and the second end of each strut coupled to the second ring by a second connector;
the second connector at the second end of each strut having a universal joint allowing rotation about a first axis parallel to the plane of the second ring and rotation about a second axis perpendicular to the first axis;
the first connector including a shuttle mounted on the track of the first ring for movement therealong and a joint having three degrees of freedom coupled to the first end of each strut, the shuttle having a gear engaging the gear track on the first ring; and
drive means for controlling the angular position of each strut second end about the second axis and drive means for rotating the shuttle gear for controlling the position of each shuttle along the circumferential gear track on the first ring.
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This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 61/209,677 filed Mar. 10, 2009, the entire disclosure of which is hereby incorporated herein by reference.
The external fixation market can be divided into two major segments: acute trauma and reconstructive. The customers, products, and needs of each segment are distinctly different. The trauma segment is dominated by modular fixators. These frames are characterized by limited componentry and very rapid application. Consequently, they are known for being fairly simple products. Most of these frames are used for temporizing fixation and quite often are only on the patient for hours or days.
The reconstructive segment leans heavily toward ring fixation, but unilateral frames also enjoy an appreciable market share. Ring fixators such as the well known Ilizarov frame are by far the most stable and capable of external fixators. Such frames are shown in U.S. Pat. Nos. 4,365,624; 4,615,338; 4,978,348; 5,702,389; and 5,971,984. Their use of a combination of pins and wires to achieve a variety of polyaxial pin/wire attachments creates this stability. They can accomplish a full six axes of deformity correction and, when applied and managed well, can correct primary deformities while not creating secondary deformities. Rotational deformities are the sole domain of the ring fixator. However, mastery of the techniques and the products themselves is a long and daunting process that it is not attractive to many users.
The present invention relates to a method for using an improved orthopaedic external fixator including a mechanism that allows two bone elements or portions to be fixed relative to one another while allowing complete repositioning of the two bone elements or portions relative to one another.
It is often necessary to realign, reposition and/or securely hold two bone elements relative to one another. For example, in the practice of medicine, bone fragments and the like must sometimes be aligned or realigned and repositioned to restore boney continuity and skeletal function. At times, this may be accomplished by sudden maneuver, usually followed by skeletal stabilization with cast, plate and screws, intramedullary devices, or external skeletal fixators.
A bone fragment can be moved, in general, from its original position as in a nonunion or malunion or from its intended position as in congenital deformities along six separate axes, a combination of three orthogonal translational axes (e.g., typical “X,” “Y” and “Z” axes) and three orthogonal rotational axes (e.g., rotation about such typical “X,” “Y” and “Z” axes).
External fixation devices are attached to the boney skeleton with threaded and/or smooth pins and/or threaded and/or smooth and/or beaded wires. Such constructs are commonly referred to as orthopaedic external fixators or external skeletal fixators. External fixators may be utilized to treat acute fractures of the skeleton, soft tissue injuries, delayed union of the skeleton when bones are slow to heal, nonunion of the skeleton when bones have not healed, malunion whereby broken or fractures bones have healed in a malposition, congenital deformities whereby bones develop a malposition, and bone lengthening, widening, or twisting.
A circumferential external fixator system was disclosed by G. A. Ilizarov during the early 1950s. The Ilizarov system includes at least two rings or “halos” that encircle a patient's body member (e.g., a patient's leg), connecting rods extending between the two rings, transfixion pins that extend through the patient's boney structure, and connectors for connecting the transfixion pins to the rings. Use of the Ilizarov system to deal with angulation, translation and rotation is disclosed in “Basic Ilizarov Techniques,” Techniques in Orthopaedics®, Vol. 5, No. 4, December 1990, pp. 55-59.
Prior art orthopaedic external fixators differ in their ability to move or adjust one bone fragment with respect to the other in a gradual fashion. Some allow gradual translation, others allow gradual rotation about two axes. The Ilizarov system can provide an external fixation device that could provide gradual correction along and about six axes; however, such a device would require many parts and would be relatively complicated to build and use in a clinical situation.
Often orthopaedic external fixators such as Ilizarov fixators must be repositioned after their initial application. Such modification may be necessary to convert from one correctional axis to another or to convert from an initial adjustment type of fixator to a weight bearing type of fixator, some of the correctional configurations not being stable enough for weight bearing.
A “Steward platform” is a fully parallel mechanism used in flight and automotive simulators, robotic end-effectors, and other applications requiring spatial mechanisms with high structural stiffness and includes a base platform, a top platform, and six variable limbs extending between the base and top platforms. See S. V. Sreenivasan et al., “Closed-Form Direct Displacement Analysis of a 6-6 Stewart Platform,” Mech. Mach. Theory, Vol. 29, No. 6, pp. 855-864, 1994.
Taylor et al. U.S. Pat. No. 5,702,389 relates to a fixator that can be adjusted in six axes by changing strut lengths only, without requiring joints to be unclamped, etc. This patent includes a first ring member or swash plate for attachment relative to a first bone element; a second ring member or swash plate for attachment relative to a second bone element. Six adjustable length struts having first ends movably attached to the first member and second ends movably attached to the second member are provided. The first ends of the first and second struts are joined relative to one another so that movement of the first end of one of the first and second struts will cause a corresponding movement of the first end of the other strut, with the first ends of the third and fourth struts joined relative to one another so that movement of the first end of one of the third and fourth struts will cause a corresponding movement of the first end of the other strut. The third and fourth struts and fifth and sixth struts are similarly joined. Second ends of the first and sixth struts joined relative to one another so that movement of the second end of one of the first and sixth struts will cause a corresponding movement of the second end of the other strut. Second ends of the second and third struts and fourth and fifth struts are formed in a similar manner. Thus, changing the length of the struts effects reposition of the bone segments.
A parallel robot is defined as a manipulator consisting of a fixed base and an end-effector with 6 degrees of freedom (DOF) that are linked together by at least two independent kinematic chains. Actuation of such a device takes place through 6 simple actuators. It is important to note that the number of actuators is equal to the number of degrees of freedom; a 6 DOF robot will require six actuators. Furthermore, each connecting chain must also have 6 degrees of freedom. Each DOF comes from a joint connecting two rigid bodies within the chain. The most commonly used joints in parallel robots are revolute (R), prismatic (P), universal (U), and spherical (S). R and P joints each grant one DOF, U joints grant two, and S joints give three. Universal joints consist of two revolute joints whose axes of rotation intersect, and are sometimes treated as two joints instead of one.
The general nomenclature for describing a parallel robot's configuration is to list the number of struts followed by the joint setup, with actuated joints underlined. Our present device is of a 3-USR (or 3-RRSR) configuration. The Base Adjustment Unit (BAU) is a modified U-joint; one of the axes of rotation is controlled through the worm-gear interface, and the other is free. The strut connects the BAU to the sliding unit via a free spherical joint, and the sliding unit revolves around the upper ring by another worm-gear interface. This leads to a kinematic chain with 2 DOF×3 chains=6 DOF.
The design shown in provisional application No. 61/209,677 filed Mar. 10, 2009 has 6 DOF while using only three struts. However, it has an alternate joint configuration. The BAU was connected to the second ring via an assembly that allowed it to freely swivel, and the strut's connection to the sliding unit was via free universal joint instead of a spherical joint. This led to a 3-RUUR (or 3-RRRRRR) configuration. Again, both configurations satisfy the necessary conditions to be considered a parallel robot.
The proximal U-joints of provisional application No. 61/209,677 are replaced with a ball and socket (or spherical joint) and the base adjustment unit (BAU) is no longer free to spin about the axis that connects it to the second ring.
An embodiment of the presently disclosed external fixation system has first and second planar at least part-circular ring elements. The centers of the first and second ring elements are spaced along an axis. The first ring element has a circumferential track extending along the part-circular circumference thereof. Three variable length struts each having first and second ends are provided. The variable length struts can be locked at a desired length after the initial positioning of the ring element. The first end of each strut is coupled by a first connector to the first ring and the second end of each strut is coupled to a second ring by a second connector. The second connector strut is fixedly coupled to the second ring in a manner which prevents rotation of the connector about an axis perpendicular to the plane of the second ring. The second connector has a U-joint having a first axis allowing for rotation in a plane parallel to the plane of the second ring. The U-joint has a second axis allowing rotation about the first axis. Three shuttles are mounted on the track of the first ring for movement there along with one shuttle coupled to the first end of each strut via the first connector. Means are provided for controlling the rotational and angular position of each strut second end and means for controlling the position of each shuttle along the circumferential track on the first ring.
The first and second rings may be complete or half circles or may be other geometric shapes, such as square or rectangular. The shuttle connected to the strut first ends may be spaced 120° around a circumference of the first ring. However, the three shuttles mounted on the first ring are movable and can move along an arc limited only by the position of the adjacent shuttle. Thus, the first ends of the three struts may move through a large portion of the first ring circumference.
Preferably, each shuttle or sliding unit can move along the track on the first ring in, for example, one to five degree increments and the angular location of the strut second end with respect to the second ring may be in five to ten degree increments. In this case, there would be between 36 and 72 holes spaced equally around the lower ring for mounting the second connector. The angular movement of the shuttle with respect to the first ring can also be infinitely variable.
Each strut first end has a connector with a spherical joint coupling the strut to the shuttle mounted on the first ring and a connector with a standard U-joint coupling each strut second end to the second ring. The U-joint has a drive system controlling the movement of the joint about one axis of the U-joint. Preferably, the drive axis is parallel to the plane of the second ring. The drive system preferably comprises a computer controlled stepper or servo motor and a gear drive system.
The external fixation system has first and second ring elements the first ring having three shuttles mounted on the ring element for controlled movement about a circumference of the ring. There are three connectors fixed to the second ring with three struts having first ends connected to a respective shuttle by connectors having a spherical or ball joint and a second end connected to a respective connector on the second ring by a standard U-joint rotatable about a first and second axis and rotatable in a controlled manner about the second axis which is perpendicular to the first axis. The first axis preferably extends parallel to the plane of the ring and the connector is fixed on the ring in a manner to prevent its rotation about the mounting hole axis. A programmable or microprocessor controller is provided for controlling the movement of the shuttle about the circumference of the first ring and for controlling the movement of the strut second end about the first axis of the connector on the second ring. This can also be adjusted manually.
An embodiment of the presently disclosed external fixation system incorporates three variable length struts that can be adjusted in length and then locked. Once locked the struts can manipulate the relative position of bone fragments to one another. The system is capable of moving in six degrees of freedom (DOF). For movement, it will incorporate either the calibration device disclosed in U.S. Pat. No. 6,017,534, the entire disclosure of which is incorporated herein by reference, or six dedicated servo or stepper motors respectively coupled to the shuttles and second ends of each strut. The calibration device or servo/stepper motors are controlled by software. The software is the interface the surgeon or user will use to determine the daily adjustments of the frame assembly. The system incorporates position sensors such as potentiometers and/or optical encoders and/or other position sensors at the moving points along the frame to not only determine the initial position, for software input/setup, but also to provide feedback to insure that the daily adjustments are being made properly.
An embodiment of the presently disclosed external fixation system has two rings and three fixable length struts having a spherical joints on a first connector on the first ring and a standard U-joints having two axes of rotation. The U-joint has a first of the two axes of rotation controlled (cannot move freely) by a worm and worm gear. The other axis of the second connector moves freely about an axis perpendicular to the first axis.
The movement of the fixed strut about the first axis and third axis is free moving. The movement about the second axis is controlled by the interaction of the worm gear and a worm situated on the second ring which worm extend parallel to the worm gear.
The driving connection of the worm to the “smart tool” described in U.S. Pat. No. 6,017,354 or servo/stepper motor will be a miter and bevel connection (where the worm has a bevel gear at one end and the tool/motor has a miter gear at its respective end). This relationship will allow the motor's miter gear to drive the worm's bevel gear which in turn drives the worm to the worm gear. This action controls one of the axes of rotation that affects its respective strut's angle (relative to the second ring).
The first connector couples the struts to the first ring by a sliding shuttle unit, which glides along two circumferential grooves on either side of the first ring. The grooves are spaced radially inwardly the toothed outer circumferential surface of the first ring. The movement of the sliding unit is controlled by the interaction of worm gear teeth (on the outside of the first ring) and a worm. Each sliding unit can be moved about the circumference of the moving ring independently. The worm is to be driven by a “smart tool” or a dedicated stepper/servo motor or a hand tool. The driving connection of the worm to the tool or motor is preferably a miter and bevel gear connection where the worm has a bevel gear at one end and the smart tool/motor has a miter gear at its respective end. Any gear box and motor could be used to drive the sliding units.
With six points of adjustment, the system will have complete control (in six axes of rotation) over the relative position of the two rings without changing strut length.
In an alternate embodiment, the external fixation system includes a first platform, a second platform, and a plurality of non-prismatic kinematic chains. By “non-prismatic,” it is meant that the kinematic chain links do not extend in length during actuation. Each kinematic chain connects the first platform to the second platform and includes at least two actuated joints. At least one actuated joints is configured to move along a perimeter of the first platform. This embodiment further includes a means for actuating the actuated joints.
As used herein when referring to bones or other parts of the body, the term “proximal” means close to the heart and the term “distal” means more distant from the heart. The term “inferior” means toward the feet and the term “superior” means toward the head. The term “anterior” means toward the front part or the face and the term “posterior” means toward the back of the body. The term “medial” means toward the midline of the body and the term “lateral” means away from the midline of the body.
While the system has been described for use in an external fixation ring system the identical structures and principles could be used in any application where platforms are manipulated such as a Stewart platform.
Referring to
As shown in
Ring 14 may be coupled to a first bone element via pins or wires and, similarly, ring 16 is coupled to a second bone element by similar pins or wires. Shuttle unit 26 is slidable about ring 14 in a track and is preferably driven by a servo motor. A second connector 29 between strut 18 and second lower ring 16 has a standard universal joint 35, which allows the strut to rotate freely about first and second axes A and B (see
Referring to
Referring to
In order to disengage worm 43 from teeth 44, mounting elements 56 and 58 are moved outwardly, thereby compressing springs 62 and 64 until chamfers 80 and 82 engage ends 84 and 86 of the housing 60. At this point, worm 43 can move downwardly in
The connection system shown in
Referring to
Referring to
Referring to
As can be seen in the figures, lever 118 can be rotated into a position in which a spring element (not shown) moves movable element 116 away from engagement with body 108 of connector 26 and consequently moves pins 124 upwardly in the figures, which allows connector 26 to be moved laterally into engagement with the ring 14. As shown in
Referring to
Referring to
The ends 28 of strut 18 are connected to shuttle 26 via a standard universal joint-type connector. As shown in
In some embodiments, sliding unit 26 in the gear portion 42 are driven by a worm gear, which in turn is driven by a stepper or servo motor having an output shaft with a bevel gear, which may be a miter gear. As such there are three independent struts having movable first and second ends and 34 connected to the first and second rings, respectively. Each of the three struts 18 may be moved around the circumference of the first ring 14 by the stepper/slash servo motors driving sliding unit 26. In addition, the second end 34 of rod 18, although circumferentially fixed in a single hole 24 of ring 16, can be rotated in planes perpendicular to the plane of ring 16 by its dedicated stepper or servo motor. The combination of these movements is capable of orienting ring 16 and ring 14 in an infinite number of angular positions with respect to one another. This change in orientation can be accomplished with fixed length struts 18.
The external fixation system of the present invention is normally supplied as a kit with a plurality of rings of different diameters, some of which are either fully circular rings or partial rings allowing their placement over the limb to be treated in a medial-lateral direction. In addition, struts 18 of various fixed lengths can be provided in the kit to produce various axial distances between the centers of the first and second rings 14, 16, respectively. Each strut 18 supplied has first and second ends 28, 34 capable of being connected to the sliding unit 26 and second ring connector 29 as described above.
A controller will also be provided, including microprocessors programmed to implement the various inputs to these six steppers or servo motors of the system. With reference to
Any Point in Space
P(X, Y, Z)
X=r sin(θ)cos(φ)
Y=r sin(θ)sin(φ)
Z=r cos(θ)
The Points at the End of the Struts
These make up the three coplanar points that will connect the struts to the upper ring. They will always be coplanar as they are all connected to a common ring.
Point 1 (P1i):
X1=r sin(θ)cos(φ)
Y1=r sin(θ)sin(φ)
Z1=r cos(θ)
Point 2 (P2):
X2=r sin(θ)cos(φ)+d sin(15)
Y2=r sin(θ)sin(φ)+d cos(15)
Z2=r cos(θ)
Point 3 (P3s):
X3=r sin(θ)cos(φ)+d cos(15)
Y3=r sin(θ)sin(φ)+d sin(15)
Z3=r cos(θ)
The Vectors from P1 to P2 and P1 to P3
Using the three points at the end of the struts, we can find two vectors on the plane.
P1P2=â=<(X2−X1),(Y2−Y1),(Z2−Z1)>
P1P3=b<(X3−X1),(Y3−Y1),(Z3−Z1)>
The Normal Vector of Plane 2 that the Points P1, P2 and P3 Sit on
Using the two vectors on the plane, we can find the normal vector.
For simplicity's sake, we'll set vector “n” to: n=<a, b, c>
The Equation of “Plane 2” that P1, P2 and P3 sit on
The following describes the upper ring's plane at any given time.
General equation of a Plane: AX+BY+CZ+D=0
To solve for the equation of the plane we must find A, B, C and D by setting the determinant of the matrix below equal to zero
Where the coefficient of X is A, the coefficient of Y is B, coefficient of Z is C and the rest is the constant D.
Equation of Sphere
To solve for the upper ring we must find the equation of a sphere. This sphere will share the upper ring's center point and radius “R1”. The sphere will also have P1, P2 and P3 on its surface. The plane we solved for above passes through the sphere's center and contains P1, P2 and P3. Therefore, the intersection of this sphere and the plane will describe the equation of the circle we are ultimately solving for to represent the upper ring.
Since P1, P2 and P3 are on the sphere's surface, the distance from these points to the center of the sphere will be equal. Setting up the following three equations will allow us to solve for the center point (Xc, Yc, Zc).
Given R1, P1, P2, P3 and the General Equation of a Sphere:
(X−Xcenter)^2+(Y−Ycenter)^2+(Z−Zcenter)^2=R1^2
We can solve for (Xc, Yc, Zc):
(X1−Xc)^2+(Y1−Yc)^2+(Z1−Zc)^2=R1^2
And
(Xc−X1)^2+(Yc−Y1)^2+(Zc−Z1)^2=(Xc−X2)^2+(Yc−Y2)^2+(Zc−Z2)^2
And
(Xc−X1)^2+(Yc−Y1)^2+(Zc−Z1)^2=(Xc−X3)^2+(Yc−Y3)^2+(Zc−Z3)^2
Solve for (Xc, Yc, Zc)
The Cartesian Equation of the Circle
Given the center (Xc, Yc, Zc) (from the sphere above), the normal vector n=<a, b, c> (from the plane) and the three points P1, P2 and P3 (on the circle); the Cartesian representation of the circle is:
(X−Xc)^2+(Y−Yc)^2+(Z−Zc)^2=R1^2
And
X[y3(z1−z2)+y1(z2−z3)+y2(−z1+z3)]+Y[x3(−z1+z2)+x2(z1−z3)+x1(−z2+z3)]+Z[−x2*y1+x3*y1+x1*y2−x3y2−x1*y3+x2*y3]+[x3*y2*z1+x2*y3*z1−x3*y1*z2+x1*y3*z2+x2*y1*z3−x1*y2*z3]=0
Parametric Equation of Circle
With the center being (Xc, Yc, Zc) (from the sphere above) and the normal vector being n=<a, b, c> (from the plane), the Parametric representation of the ring is:
X(t)=Xc+(a*c*R*cos(t)−b*R*sin(t)/(a^2+b^2)^(½)
Y(t)=Yc+(b*c*R*cos(t)+a*R*sin(t)/(a^2+b^2)^(½)
Z(t)=Zc−R*cos(t)*(a^2+b^2)^(½)
Where: 0≦t≦2 n
Thus, to align a first bone element with respect to a second bone element, one utilizes the above mathematical model to design software. The software will first consider the initial position of the rings with respect to the bone elements. The final position of the frame with the aligned bones will be determined by the software, taking into account the size and position of the rings and struts. The software will calculate the shortest trajectory from the initial to final position of the moving ring, generating the intermediate positions of the moving elements on the ring, and the angular rotations of the struts at the fixed ends, using a form of ring kinematics to get the necessary values. The ring kinematics will be derived by applying the mathematical formula above to determine the iterations required to get from the initial position to the final position. These iterations will be generated with a constraint on the maximum possible correction per day as defined by the surgeon in terms of the maximum distraction rate.
Referring to
Sliding unit 26 operates as described above in connection with the embodiment depicted in
As shown in
Referring to
In the embodiment depicted in
First and second platforms 316, 314 are substantially similar to first and second rings 14, 16, as described above, and to each other. Nevertheless, first and second platforms 314, 316 may be made of different materials. For example, in certain embodiments, first platform 314 is wholly or partly made of aluminum, while second platform 316 is wholly or partly made of a radiolucent carbon fiber or a reinforced polymer such as polyetheretherketone (PEEK).
As seen in
With reference to
With reference to
Referring again to
Referring to
With continued reference to
Referring again to
Clamp body 383 of sliding unit 326 holds parts of third revolute joint 339, i.e., gear portion 342 and worm 343. Worm 343 is configured to engage gear portion 342. As a result, gear portion 342 pivots about axis I upon rotation of worm 343 about axis K when gear portion 342 and worm 343 are engaged to each other. As discussed with regard to drive connector 43, drive connector 343 can be driven by any suitable mechanical or electro-mechanical tool or means. For example, worm 343 may be driven by a “smart tool” as described in U.S. Pat. No. 6,017,354, a dedicated stepper/servo motor or a hand tool. Since third revolute joint 339 can be pivoted about pivot pin 340 through the actuation of worm 343, third revolute joint 339 is deemed an actuated joint. For the purposes of the present disclosure, an “actuated joint” means any joint capable of being driven or actuated by a mechanical or electro-mechanical tool. In the embodiment illustrated in
With reference to
The structure and operation enabling movement of worm 343 between the engaged and disengaged positions are identical to the structure and operation of worm 43 (see
Referring again to
With reference to
When worm 406 is located in the engaged position relative to worm gear 406, worm 406 can revolve along the perimeter or circumference of second platform 316 upon rotation of worm 406 about axis L. Worm 406 can be driven (that is, rotated about axis L) with any of suitable mechanical or electro-mechanical tool or means such as a “smart tool” a dedicated stepper/servo motor or a hand tool. Given that first revolute joint 395 can be actuated through the rotation of worm 406 about axis L, first revolute 395 is deemed an actuated joint. As discussed above, third revolute joint 339 is also considered an actuated joint. Spherical joints 308 are not considered actuated joints because these joints are not driven or actuated. Therefore, each kinematic chain 390 of the embodiment shown in
With continued reference to
The structure and operation of pins 410 are identical to the structure and operation of pins 110 (see
Sliding unit 326 additionally includes a first sheet 450 mounted on base 412 for maintain the position of the first pair of pins 410 and a second sheet 452 mounted on movable arm 416 for maintain the position of the second pair of pins 424.
As discussed above, movable arm 416 can move toward and away from base 412. In some embodiments, a bolt 418 or any other suitable apparatus controls the movement of movable arm 416 relative to base 412 and helps secure sliding unit 426 to second platform 416. Clamp body 383 includes a threaded hole 460 positioned and dimensioned to receive and engage bolt 418. Bolt 418 can secure movable arm 416 to clamp body 383 when securely received within threaded hole 460. A user can move movable arm 416 toward or away from base 412 by screwing or unscrewing bolt 418 from threaded hole 460.
Referring to
In use, a physician may employ external fixation system 300 as well as the alternate embodiments to perform an osteotomy. Osteotomy may be performed at any long bone such as the tibia and the femur. In an exemplary method, the physician attaches the first platform to a first bone segment with any suitable apparatus such as wires or pins. Then, the physician attaches the second platform to a second bone segment with wires or pins. After securing the first and second platforms to different bone segments, the physician should determine the proper relative position of the first bone segment with respect to the second bone segment (i.e., a predetermined position). Using the software described above, the physician then uses a mathematical correlation of the relative position of the first platform with respect to the second platform to determine the new locations for the actuated joints required to reposition the first bone segment to the predetermined position with respect to the second bone segment. Next, the physician actuates the actuated joints to move said actuated joints to the new determined locations. Other methods of utilizing the disclosed external fixation system are envisioned. Irrespective of the methods employed, the presently disclosed external fixation system provide at least six degrees of freedom.
These components come together to allow the full assembly six degrees of freedom: three translational (x,y,z), and three rotational (pitch, roll, yaw). It is worth noting that the assembly does this with three struts instead of the normal six associated with a Gough/Stewart platform. The mathematics of this system is described in Alizade et al. Mech. Mach. Theory Vol. 29, No. 1, pp. 115-124, 1994 which is incorporated herein by reference in its entirety.
Many authors have proposed six degrees of freedom robots with only three legs that will have two actuators per leg (hence they are not fully parallel). This allows one to decrease the risk of interference between the legs (thereby increasing the workspace size), but has the drawback of reducing the stiffness while increasing the positioning errors.
Each of the three kinematic chains connecting the bottom ring to the top demonstrates six degrees of freedom from its joints in the configuration shown. The first comes from the rotation of the sliding unit about the ring 14. The second comes from the rotation of the strut about the sliding unit 26 via yoke joint 202. The third comes from the extension of the strut via its prismatic joint. The final three come from the three degrees of rotation allowed for by the spherical or ball joint. To be defined as a parallel robot, the design must have the same number of actuators as it has degrees of freedom. As there are six degrees of freedom, there are six actuators: one prismatic (within the strut) and one rotational (between the sliding unit 26 and the gear) for each of the three legs. Each actuator provides the upper ring with one degree of freedom. Alizade et al. (id.) have explored the range of motion in a setup such as this already, demonstrating the size of the assembly's workspace and analyzing both forward and rear displacement. They also declared that this assembly has a distinct advantage over the Steward/Gough platform in its ability to produce pure rotation.
The six degrees of freedom provided by these designs allow it the unique property of having a “virtual hinge.” When repairing a deformed bone, it is essential that re-alignment takes place centered on the Center of Rotation of Angulation (CORA)—the point at which the proximal mechanical axis and distal mechanical axis intersect. In older systems (e.g. Ilizarov), it was essential to build a physical hinge into the assembly that aligned perfectly with the CORA. If a physician noticed halfway through the patient's treatment that the alignment of this hinge was off, it became necessary to physically repair the system and reposition the hinge. The virtual hinge afforded by six degrees of freedom greatly simplifies this process. No actual hinge must be installed initially; the two rings are able to generate rotation about any single line, forming the “virtual hinge” there. If a physician notices that the initially chosen line was inaccurate, all that must be done to fix the prescription is to simply correct the line acting as the virtual hinge. This can quickly and easily be done using software.
Each of the six struts 718 has a proximal and distal end. At the proximal end, the strut is connected to a ring with a sliding unit 726. At its distal end, it is bolted to the opposing ring. The six sliding units 726 move about the perimeter of the rings 714, 716 to adjust the effective distance between the rings. Sliding in the direction that increases the angle θ (
When the external fixation system 700 is being set up in surgery, the struts' length can be changed to attain the optimal starting position (Optimal Position, see
When the struts are all equal length and each sliding unit's distal end is closest to the proximal end of its neighboring strut (see
Whenever the initial configuration of the struts 718 is such that the distal end of each strut is closest to the proximal end of its neighboring strut, see
Strut interference occurs when one strut's position prohibits another strut from moving past. This effectively limits the range of motion. By setting up the system 700 in the optimal position, one limits the effects interference has on the range of motion, thus maximizing the possible adjustments from the starting point.
In many cases the rings 714, 716 will not be parallel and inline immediately following surgery. If the struts were all the same length and the rings 714, 716 were not parallel, one could not achieve the optimal position of the struts. It is for this reason that the struts must be adjustable in length. Ideally, the system 700 will be positioned in the optimal position regardless of the relative position of one ring 714, 716 to another. As can be seen in
Alternatively, different length struts could be provided that “snap” in to the system. This would allow the surgeon to get close to the optimal position. As one decreases the iterative different in length of the struts available, the probability of exactly attaining the optimal position increases. As a corollary, this increases the number of struts that are to be offered in a kit and the complexity of the setup. Allowing for an adjustable length strut would reduce the number of struts required in a kit to six. It is important to note that the adjustable length does not in any way control the movement of the rings. Once the struts'lengths are set intraoperatively (while installing the frame), they are fixed for the entirety of the frame's movement. This is inherently different than prior art spatial frames because they require the struts to adjust length to make any movement. With the present design, a user could adjust the struts 418 to the appropriate length before they were put on the frame, fix the lengths and install them into the frame. This would insure that no strut length adjusting occurred while struts were on the frame.
The length of the struts needed is dependent on the initial position of the system 700. For example, if the system 700 is set up such that the rings 714, 716 are parallel and vertically inline (See
As shown in
The following mathematical expressions describe the movement and position of rings 714 and 716. This mathematical representation of a six strut platform is described by the position of one platform relative to the other.
The rotation of the moving platform relative to the base platform can be expressed as the rotation of the (x′,y′,z′)-coordinate system relative to the origin coordinate-system (x,y,z). The angles for the rotation are set to (Ψ,Φ,Θ).
The vector {right arrow over (OC)} describes the position of the center of the moving platform relative to the base platform and is represented by
{right arrow over (OC)}={right arrow over (OA)}+{right arrow over (AB)}+{right arrow over (BC)} (1)
This equals to
|{right arrow over (OC)}|=|{right arrow over (OA)}+{right arrow over (AB)}+{right arrow over (BC)}| (2)
Equation (2) squared delivers an equation in which most of the components can be replaced by known variables.
∥{right arrow over (OC)}∥2=∥{right arrow over (OA)}∥2+∥{right arrow over (AB)}∥2+∥{right arrow over (BC)}∥2+2(∥{right arrow over (OA)}∥∥{right arrow over (AB)}∥+∥{right arrow over (AB)}∥∥{right arrow over (BC)}∥+∥{right arrow over (BC)}∥∥{right arrow over (OA)}∥) (3)
With ∥{right arrow over (AB)}∥=ρ and ∥{right arrow over (OA)}∥=α
The vector {right arrow over (BC)} is described in the origin base coordinate system and equals its description in the rotated coordinate system x′,y′,z′ when it's multiplied with the rotation matrix R.
({right arrow over (BC)})(x,y,z)=R({right arrow over (BC)})(x′,y′,z′) (4)
The rotation matrix rotates each axis with the according angle (Ψ,Φ,Θ)).
R=[Rz(ψ)·Ry(Θ)·Px(Φ)] (5)
This results in the following rotation matrix:
Substituting all known variables into equation (3) gives us:
∥{right arrow over (OC)}∥2=α2+ρ2+∥{right arrow over (BC)}+2[αρ+ρ(R{right arrow over (BC)})+α(R{right arrow over (BC)})] (7)
Given six unique struts, we have six unknowns: (x′,y′,z′) which are coordinates of the point C and (Ψ,Φ,Θ) which are the angles of rotation of the normal to the circle with the center C. Equation (7) would give us 6 equations for the 6 unknowns from which the location of C can be calculated. Center C and radius b can be used to describe the position of the moving platform relative to the base platform.
With reference to
{right arrow over (OB)}={right arrow over (OC)}+{right arrow over (CB)} (8)
With the known rotation of the coordinate system, the circle lies in a plane spanned by the x′- and y′-axes. The normal to this plane is the z′-axes. The radius b rotates around this normal with the angle t. Therefore the circle is described by equation (9):
{right arrow over (OB)}(t)={right arrow over (OC)}+b cos(t)x′+b sin(t)y′ (10)
Using the rotation matrix derived from the equations above, we get the equation for a ring with respect to the origin coordinate system (x,y,z):
{right arrow over (OB)}(t)={right arrow over (OC)}+b cos(t)Rx+b sin(t)Ry (10)
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
Edelhauser, Adam John, Tomasheski, Richard J.
Patent | Priority | Assignee | Title |
10010346, | Apr 20 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Ring hole planning for external fixation frames |
10010350, | Jun 14 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Gear mechanisms for fixation frame struts |
10123881, | Apr 20 2006 | Moskowitz Family LLC | Electronically controlled artificial intervertebral disc with motor assisted actuation systems |
10154884, | Jun 02 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Software for use with deformity correction |
10180207, | Jul 13 2017 | KOZUB, DANYLO; SHAPOVAL, IURII | Stand |
10194944, | Feb 19 2013 | Stryker European Operations Holdings LLC | Software for use with deformity correction |
10251705, | Jun 02 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Software for use with deformity correction |
10299830, | Mar 15 2013 | Biomet Manufacturing, LLC | Clamping assembly for external fixation system |
10306984, | Aug 30 2016 | The Boeing Company | Toroidal support structures |
10368913, | Aug 10 2015 | STRYKER EUROPEAN HOLDINGS III, LLC | Adjustment instrument with tactile feedback |
10470800, | Mar 13 2013 | DePuy Synthes Products, Inc. | External bone fixation device |
10492832, | Oct 24 2014 | STRYKER EUROPEAN HOLDINGS III, LLC | Methods and systems for adjusting an external fixation frame |
10596699, | Oct 23 2017 | Parallel mechanism masticator and chewing apparatus | |
10603112, | Jun 02 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Software for use with deformity correction |
10603122, | Feb 17 2016 | Rowan University | Surgical robot |
10746928, | Sep 30 2016 | 3SAE Technologies, Inc. | Multi-axis positioning method |
10835318, | Aug 25 2016 | DEPUY SYNTHES PRODUCTS, INC; Synthes GmbH | Orthopedic fixation control and manipulation |
10874433, | Jan 30 2017 | STRYKER EUROPEAN HOLDINGS III, LLC | Strut attachments for external fixation frame |
10881433, | Feb 19 2013 | Stryker European Operations Holdings LLC | Software for use with deformity correction |
10932857, | May 19 2010 | DePuy Synthes Products, Inc. | Orthopedic fixation with imagery analysis |
10952867, | Apr 20 2006 | Moskowitz Family LLC | Electronically assisted medical device |
10959766, | Oct 25 2017 | WRIGHT MEDICAL TECHNOLOGY, INC | Wire tensioner tip |
11020186, | Jun 02 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Software for use with deformity correction |
11083495, | Apr 20 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Ring hole planning for external fixation frames |
11083497, | Aug 10 2015 | STRYKER EUROPEAN HOLDINGS III, LLC | Adjustment instrument with tactile feedback |
11207103, | Oct 24 2014 | STRYKER EUROPEAN HOLDINGS III, LLC | Methods and systems for adjusting an external fixation frame |
11269143, | Sep 30 2016 | 3SAE TECHNOLOGIES, INC | Multi-axis positioner |
11304757, | Mar 28 2019 | Synthes GmbH | Orthopedic fixation control and visualization |
11334997, | Apr 03 2020 | Synthes GmbH | Hinge detection for orthopedic fixation |
11337761, | Feb 07 2019 | STRYKER LEIBINGER GMBH & CO KG | Surgical systems and methods for facilitating tissue treatment |
11389256, | Feb 17 2016 | Rowan University | Surgical robot |
11439436, | Mar 18 2019 | Synthes GmbH | Orthopedic fixation strut swapping |
11491021, | Apr 20 2006 | Moskowitz Family LLC | Electronically assisted medical device |
11504160, | Jun 14 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Gear mechanisms for fixation frame struts |
11543230, | Jun 07 2019 | Carl Zeiss Industrielle Messtechnik GmbH | Articulating probe |
11553965, | Jun 02 2016 | Holdings LLC | Software for use with deformity correction |
11648035, | Mar 18 2019 | Synthes GmbH | Orthopedic fixation strut swapping |
11666126, | Oct 19 2018 | Mechanism combining articulation and side-shift | |
11681100, | Sep 30 2016 | 3SAE TECHNOLOGIES, INC | Multi-axis positioner |
11707801, | Aug 23 2018 | SLONE GEAR INTERNATIONAL, INC | Alignment of laser for gear inspection |
11723690, | Jan 30 2017 | STRYKER EUROPEAN HOLDINGS III, LLC | Strut attachments for external fixation frame |
11771466, | Apr 20 2016 | Stryker European Operations Holdings LLC | Ring hole planning for external fixation frames |
11819246, | Feb 19 2013 | Stryker European Operations Holdings LLC | Software for use with deformity correction |
11893737, | Apr 03 2020 | Synthes GmbH | Hinge detection for orthopedic fixation |
11896313, | May 19 2010 | DePuy Synthes Products, Inc. | Orthopedic fixation with imagery analysis |
11918266, | Oct 25 2017 | Wright Medical Technology, Inc. | Wire tensioner tip |
11918292, | Aug 25 2016 | DePuy Synthes Products, Inc. | Orthopedic fixation control and manipulation |
11951017, | Apr 20 2006 | Moskowitz Family LLC | Electronically assisted medical device |
11971578, | Sep 30 2016 | 3SAE Technologies, Inc. | Multi-axis positioner |
11974781, | Jun 14 2016 | Stryker European Operations Holdings LLC | Gear mechanisms for fixation frame struts |
8574232, | Nov 13 2012 | Texas Scottish Rite Hospital for Children | External fixation connection rod for rapid and gradual adjustment |
8864750, | Feb 18 2008 | Texas Scottish Rite Hospital for Children | Tool and method for external fixation strut adjustment |
9078700, | Feb 12 2008 | Texas Scottish Rite Hospital for Children | Fast adjust external fixation connection rod |
9155559, | Feb 08 2008 | Texas Scottish Rite Hospital for Children | External fixator strut |
9186180, | Mar 08 2013 | STRYKER EUROPEAN HOLDINGS III, LLC | Rose gear for external fixation clamp |
9295493, | Feb 05 2008 | Texas Scottish Rite Hospital for Children | External fixator ring |
9304092, | Sep 18 2012 | Nordson Corporation | Apparatus for examining test bodies |
9359176, | Mar 20 2012 | GM Global Technology Operations LLC | Movement device configured for moving a payload |
9381042, | Nov 13 2012 | Texas Scottish Rite Hospital for Children | External fixation connection rod for rapid and gradual adjustment |
9443302, | Aug 20 2010 | ORTHOFIX S R L | Method and system for roentgenography-based modeling |
9456849, | Feb 12 2008 | Texas Scottish Rite Hospital for Children | Fast adjust external fixation connection rod |
9579122, | Jul 07 2014 | Texas Scottish Rite Hospital for Children | Collapsible fixator system |
9610102, | Sep 26 2013 | STRYKER EUROPEAN HOLDINGS III, LLC | Bone position tracking system |
9642649, | May 19 2010 | DEPUY SYNTHES PRODUCTS, INC | Orthopedic fixation with imagery analysis |
9675382, | Mar 13 2013 | DEPUY SYNTHES PRODUCTS, INC | External bone fixation device |
9681892, | Feb 08 2008 | Texas Scottish Rite Hospital for Children | External fixator strut |
9717528, | Apr 01 2014 | STRYKER EUROPEAN HOLDINGS III, LLC | External fixator with Y strut |
9788861, | Mar 13 2013 | DePuy Synthes Products, Inc. | External bone fixation device |
9808289, | Feb 05 2008 | Texas Scottish Rite Hospital for Children | External fixator ring |
9827011, | Mar 15 2013 | Biomet Manufacturing, LLC | Polyaxial pivot housing for external fixation system |
9895167, | Apr 20 2016 | STRYKER EUROPEAN HOLDINGS III, LLC | Ring hole planning for external fixation frames |
9959683, | Mar 15 2013 | ORTHOFIX S R L | Method of determining the position of an object using projections of markers or struts |
9962188, | Oct 29 2013 | EMERGE MEDICAL INC | External fixation system and methods of use |
9987043, | Oct 24 2014 | STRYKER EUROPEAN HOLDINGS III, LLC | Methods and systems for adjusting an external fixation frame |
Patent | Priority | Assignee | Title |
3977397, | Nov 27 1974 | Surgical compression-distraction instrument | |
4365624, | Jan 16 1979 | Jaquet Orthopedie SA | External bone-anchoring element |
4554915, | Mar 08 1983 | SMITH & NEPHEW RICHARDS, INC | Bone fixation frame |
4615338, | Sep 18 1985 | KURGANSKY NAUCHNO-ISSLEDOVATELSKY INSTITUT EXPERIMENTALNOI I KLINICHESKOI ORTOPEDII I TRAVMATOLOGII | Automatic compression-distraction apparatus |
4768524, | Feb 28 1986 | Device for immobilizing a bone structure, especially intended for orthopedic use | |
4784125, | Jan 24 1985 | Stryker Trauma SA | Arcuate element and external fixation device containing same for osteosynthesis and osteoplasty |
4819496, | Nov 17 1987 | UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE SECRETARY OF THE AIR FORCE | Six degrees of freedom micromanipulator |
4889111, | Apr 02 1984 | Bone growth stimulator | |
4976582, | Dec 16 1985 | DEMAUREX, MARC-OLIVIER; DEMAUREX, PASCAL | Device for the movement and positioning of an element in space |
4978348, | May 26 1988 | VSESOJUZNY KURGANSKY NAUCHNY TSENTR VOSSTANOVITELNAYA TRAVMATOLOGIA I ORTOPEDIA, | Compression-distraction apparatus for osteosynthesis |
5028180, | Sep 01 1989 | Giddings & Lewis, LLC | Six-axis machine tool |
5087258, | Jun 19 1987 | Ring splint to set, affix and regulate the tension position of bone segments | |
5122140, | Aug 23 1990 | Stryker Trauma SA | Dynamic external fixation device |
5179525, | May 01 1990 | UNIVERSIYT OF FLORIDA RESEARCH FOUNDATION, INCORPORATED; University of Florida Research Foundation, Incorporated | Method and apparatus for controlling geometrically simple parallel mechanisms with distinctive connections |
5279176, | Jul 20 1992 | TAHMASEBI, FARHAD; TSAI, LUNG-WEN | Six-degree-of-freedom parallel "minimanipulator" with three inextensible limbs |
5301566, | Jul 20 1992 | The United States of America as represented by the Administrator of the | Simplified and symmetrical five-bar linkage driver for manipulating a Six-Degree-of-Freedom Parallel "minimanipulator" with three inextensible limbs |
5358504, | May 05 1993 | Smith & Nephew Richards, Inc. | Fixation brace with focal hinge |
5372597, | May 12 1993 | SMITH & NEPHEW RICHARDS, INC | Supination-pronation device |
5397322, | Aug 03 1990 | Stryker Trauma SA | Manipulator for external bone fixation devices |
5568993, | Dec 21 1994 | UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE SECRETARY OF COMMERCE | Strut structure and rigid joint therefor |
5702389, | Mar 01 1995 | Smith & Nephew Richards, Inc. | Orthopaedic fixation device |
5709681, | Sep 19 1995 | Device for osteosynthesis | |
5728095, | Mar 01 1995 | Smith & Nephew, Inc | Method of using an orthopaedic fixation device |
5870834, | Oct 22 1996 | Sheldon/Van Someren, Inc. | Six-axis metrology sensor device |
5891143, | Oct 20 1997 | Smith & Nephew, Inc | Orthopaedic fixation plate |
5971984, | Mar 01 1995 | Smith & Nephew, Inc | Method of using an orthopaedic fixation device |
6021579, | Apr 01 1998 | Joseph M., Schimmels; SCHIMMELS, JOSEPH M | Spatial parallel compliant mechanism |
6030386, | Aug 10 1998 | Smith & Nephew, Inc | Six axis external fixator strut |
6086283, | Sep 25 1996 | University of Florida | Universal joint for coordinate measuring device |
6099217, | Dec 20 1995 | Device for spatially moving a body with three to six degrees of freedom in a controlled manner | |
6129727, | Mar 02 1999 | Smith & Nephew, Inc | Orthopaedic spatial frame apparatus |
6196081, | Feb 03 1998 | Hexel Corporation | Systems and methods employing a rotary track for machining and manufacturing |
6277118, | Jan 31 2000 | Biomet Manufacturing, LLC | External fixator including an angular correction module and related method |
6355037, | Dec 05 2000 | Smith & Nephew, Inc. | Apparatus and method of external skeletal support allowing for internal-external rotation |
6428540, | Nov 13 1996 | Synthes USA, LLC | Device for repositioning fractured bone fragments |
6648583, | Aug 05 1999 | Parallel kinematics mechanism with a concentric spherical joint | |
6671975, | Dec 10 2001 | ALIO INDUSTRIES, INC | Parallel kinematic micromanipulator |
6701174, | Apr 07 2000 | Carnegie Mellon University | Computer-aided bone distraction |
6769194, | Dec 10 2001 | ALIO INDUSTRIES, INC | Parallel kinematic micromanipulator |
7127660, | Jan 14 2004 | Hitachi Global Storage Technologies Netherlands B.V. | Method, apparatus and program storage device for correcting a burst of errors together with a random error using shortened cyclic codes |
7282052, | Sep 17 2002 | AMDT HOLDINGS, INC | Unilateral fixator |
7422593, | Dec 08 2005 | Biomet Manufacturing, LLC | External fixation system |
20020010465, | |||
20050015087, | |||
20050215997, | |||
20050251136, | |||
20060184169, | |||
20070055234, | |||
20070161984, | |||
20070250071, | |||
20080021451, | |||
20100087819, | |||
DE202006006734, | |||
FR2576774, | |||
FR2756025, | |||
RE40914, | Oct 20 1997 | Smith & Nephew, Inc. | Orthopaedic fixation plate |
WO115611, | |||
WO3086213, | |||
WO9418898, |
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